Anatomy Exam Muscles of the Rotator Cuff 4 — Questions and Answers
Question 1: In the 'empty can test,' the arm is placed in what position to isolate the supraspinatus?
- 90° abduction with internal rotation, as if emptying a can (Correct answer)
- 90° flexion with external rotation
- 45° abduction with neutral rotation
- Full elevation with pronation
Correct answer: 90° abduction with internal rotation, as if emptying a can
The empty can test positions the arm at 90° abduction with internal rotation (thumb pointing down), isolating supraspinatus tension.
Question 2: Which rotator cuff muscle inserts on the inferior facet of the greater tubercle?
- Teres minor (Correct answer)
- Infraspinatus
- Supraspinatus
- Subscapularis
Correct answer: Teres minor
The teres minor inserts onto the inferior facet of the greater tubercle, below the infraspinatus.
Question 3: A 'SITS' mnemonic is used to remember the rotator cuff muscles. What does 'T' represent?
- Teres minor (Correct answer)
- Trapezius
- Teres major
- Triceps
Correct answer: Teres minor
In SITS (Supraspinatus, Infraspinatus, Teres minor, Subscapularis), the 'T' stands for Teres minor.
Question 4: Damage to the suprascapular nerve at the spinoglenoid notch would selectively affect which muscle?
- Infraspinatus only (Correct answer)
- Supraspinatus only
- Both supraspinatus and infraspinatus
- Teres minor only
Correct answer: Infraspinatus only
Compression at the spinoglenoid notch affects the suprascapular nerve after it branches to the supraspinatus, so only the infraspinatus is denervated.
Question 5: Which of the following is NOT a function of the rotator cuff as a group?
- Elevating the clavicle (Correct answer)
- Stabilizing the glenohumeral joint
- Depressing the humeral head
- Rotating the humerus
Correct answer: Elevating the clavicle
The rotator cuff muscles do not act on the clavicle; clavicle elevation is performed by the trapezius and sternocleidomastoid.
Question 6: In a massive rotator cuff tear involving the supraspinatus and infraspinatus, which movement would be most severely compromised?
- External rotation and abduction (Correct answer)
- Internal rotation and adduction
- Horizontal abduction and flexion
- Extension and circumduction
Correct answer: External rotation and abduction
Loss of both the supraspinatus (abduction) and infraspinatus (external rotation) severely compromises these combined movements.
Question 7: The subscapularis is separated from the scapula by which bursa?
- Subscapular bursa (subcoracoid bursa) (Correct answer)
- Subacromial bursa
- Subdeltoid bursa
- Infraspinatus bursa
Correct answer: Subscapular bursa (subcoracoid bursa)
The subscapular (subcoracoid) bursa lies between the subscapularis muscle and the neck of the scapula, reducing friction.
Anatomy Exam Muscles of the Rotator Cuff 4
In the 'empty can test,' the arm is placed in what position to isolate the supraspinatus?